1. Field of the Invention
The present invention relates to a method for removing a substance from a medium and, more particularly, to such a method which is particularly well suited to the removal of contaminants, such as toxic substances, from virtually any site and in situ as well as after removal of the medium to a remote location.
2. Description of the Prior Art
A disposal of waste materials is a perplexing concern to society, particularly with recognition in the scientific community that conventional practices are inadequate. These problems are compounded where the substances under consideration are toxic. In view of the fact that, until recently, no provision was publicly provided for the disposal of toxic substances, common practice called for the substances simply to be drained onto the ground. Thus, the conventional practice in industry, agriculture, at military installations, and by private parties was simply to allow such substances to be absorbed naturally into the soil. Containers were allowed to be drained of their residues into the soil. Vehicles of all types were allowed to drain onto the soil. Residues of toxic substances of virtually all types were disposed of in similar fashions with little or no concern for the long term effect thereof.
More recently the scientific community has recognized that the build up of such toxic substances in the soil constitutes an immediate, as well as long range, health hazard to both humans and animals. The exposure to a wide assortment of toxic substances is a cause, or significant contributing factor, to a wide variety of diseases and other physical ailments. Furthermore, it has become recognized that abandonment of such conventional disposal practices is not, in itself, adequate to remediate the hazards resulting from past practices. Thus, in many instances, toxins in the soil require extensive periods of time to dissipate to the point where they no longer constitute any health hazard. The periods of time required for such dissipation to take place may not be known. As a consequence, sites so contaminated must either be abandoned for as yet unknown periods of time, or must be remediated in order to become habitable. Since most such sites are to one degree or another of significant commercial value, considerable effort has been devoted to the development of reliable procedures for removing such contaminants from the soil.
One of the most obvious methods for soil remediation has simply been the removal of the soil so contaminated from the site and its disposal in toxic waste dumps devoted to the purpose. However, such removal is expensive and leaves the site unsuitable for most purposes without bringing in clean top soil to replace the contaminated soil which has been removed. There is a wide assortment of other remedial processes that have been developed directed toward the same objectives which include complex and expensive procedures which may or may not be adequate to the purpose. Such conventional procedures may further be characterized as affording uneven results due both to the uneven dispersal of the toxins in the soil as well as the uneven effect of such conventional remediation procedures upon the site.
Finally, governmental regulation has, in many instances, not permitted the abandonment of contaminated sites, but rather requires that such sites be cleansed of such contaminants by their present owners, or by those who contaminated the site, or by governmental agencies using funds set aside for the purpose.
Therefore, it has long been known that it would be desirable to have a method for removing a substance from a medium having particular utility in the removal of contaminants from soils and which is comparatively inexpensive in practice; which can be performed in large part by semi skilled personnel; which performs such remediation evenly over the area to which it is applied; and which can be performed to reduce the concentration of the substances to a level which can be calculated and which corresponds to that which is the objective of such remediation.